The Caribbean Sea and its watersheds show signs of environmental degradation. These fragile coastal ecosystems are susceptible to environmental impacts, in part because of their oligotrophic conditions and their critical support of economic development. Tourism is one of the major sources of income in the Caribbean, making the region one of the most ecotourism dependent in the world. Yet there are few explicit, long-term, comprehen- sive studies describing the structure and function of Caribbean ecosystems. We propose a conceptual framework using the environmental signature hypothesis of tropical coastal settings to develop a series of research questions for the reef–sea-grass–wetland seascape. We applied this approach across 13 sites throughout the region, including ecosystems in a variety of coastal settings with different vulnerabilities to environmental impacts. This approach follows the strategy developed by the Long Term Ecological Research program of the National Science Foundation to establish eco- logical research questions best studied over decades and large spatial areas.

R ecent reviews describing human impacts on coastal and marine ecosystems in the Caribbean em- phasize two major problems. First is the lack of information about processes controlling the productivity of diverse coastal ecosystems. Second is the potential long-term negative impact of human disturbances on the goods and services these ecosystems provide (Richards and Bohnsack 1990, Ogden 1997). The Caribbean Sea has been diagnosed as an eco- system showing “signs of environmental stress” (Richards

and Bohnsack 1990), representing a global trend in which human impacts on marine ecosystems are more the rule than the exception. A current debate in environmental re- source management concerns how best to understand the magnitude of ecosystem change associated with human impacts and to designate the global regions that are more susceptible to human activities (Vitousek et al. 1997). In the Caribbean Sea and its watersheds, degradation of water and land resources is related to major declines in biodiversity